WITH their almost limitless variety of kinds, heights, colours and seasons of flower, hardy perennials offer the gardener a most satisfying return for his time, trouble and outlay. Although they are more expensive initially than bedding plants or other, they are less expensive in the long run for, once planted, they live on from year to year. If a reasonably large selection is grown, flowers will be in bloom from February to November. Perennials make their greatest display during the period June to September, and although there is not a great blaze of colour during the winter months, it is a joy to see their modest displays while the majority of plants are lying low.
To achieve complete satisfaction, early, mid-season and late-flowering kinds should be planted. Either choose kinds that can adapt themselves to a given site, or choose a site suitable for the plants selected.
Until Victorian times there had been little scope for hardy perennials, which, being so varied, could not be confined and restricted in the then current formal styles of decorative gardening. So the herbaceous border emerged as a compromise, with plants growing more freely, but within straight lines. Though this became the conventional means of growing perennials, recent developments in design or layout have proved to be more satisfying.
It was not realized that, for freedom from trouble and for the most rewarding display, the conventional herbaceous border was not the best way to grow hardy perennials. An open situation is natural for the majority of plants since ample light and air are necessary for sturdy growth. Many will grow and flower where these essentials are lacking in some respect, but, depending on their adaptability, they are likely to fall short of the natural perfection of which they are capable.
LIGHT AND AIR
Many conventionalare conducive to weak growth. A hedge or fence as backing, the presence of trees or shrubs, and overcrowding among the plants themselves are all harmful. Not only is light often restricted by such overshadowing, but so is the free circulation of air. These restrictions make for stem weakness.
Another disadvantage of the conventional border is that many plants may be much too tall for so narrow a strip. In an open place with adequate spacing, such plants increase the number of their stems from year to year and keep to their normal height; in a narrow strip, with a wall, hedge or tree backing, they grow taller in their search for sun and air, and the result proves detrimental to shorter plants in the same border. But if this type of border is planted with discrimination it can be most satisfying.
Most hardy perennials are very adaptable as to. Some plants like it to be richer or moister than others, but there is sufficient variety available from which to make the right selection for almost any situation. It is therefore possible to have perennials flourishing in any garden, even in closely built-up areas.
PREPARATION OF SITE
If possible choose a site where sun and air are not restricted, and aim for the maxi-mum width possible. Destroy all perennial. Couch, ground elder and nettles can be eliminated by chemicals or by thorough and repeated digging to expose them to sun and wind. Alternatively, they can be effectively buried. This involves trenching but is worth doing. With a spade skim off the few inches of top-soil that contain the roots of such weeds, upturn it in the bottom of the trench, tread in and then cover with 9 to 12 in. of weed-free soil.
In general, hardy perennials do not demand richness, but if the soil is poor they do respond to manure. Farmyard manure, rottedor peat with fertilizer added are all of value. If the natural soil is dark with humus or is of good loamy texture, use only organic fertilizer at the rate of 2 or 3 oz. per sq. yd. to give the plants the good start that is important to them.